In the world of mechanical devices there are many examples of mechanical action driven by a spring force. Examples of such mechanical systems include map or plan rollers, window or opening covers, hinged containers and can or drum feeding mechanisms.
In some of these applications it is desirable to provide a latching mechanism to maintain the spring in its pre-loaded state until such a time, as the force of action is required. Traditionally, the latching mechanism has been in the form of a secondary mechanical device such as a pawl, latch or catch. These additional mechanisms add complexity and cost to spring loaded systems and may ultimately affect the reliability of the system.
A bi-stable ribbon spring has unique characteristics in that the spring has a first stable linear state and a second stable coiled state. Such springs have been incorporated into “slap bracelets” which are short (approximately 6″ to 9″ long) bi-stable springs contained within a cloth sack. When flexed the slap bracelet self coils around a user wrist assuming a first stable coiled state. The bracelet can be removed and straightened to assume a second stable linear state. Such bi-stable snap springs have also been labeled and used as tape measures that can assume a first stable linear state and a second stable coiled state.
In the area of plan or map holders there is a need for a convenient, simple mechanism that will maintain the stability of plan or map in either a rolled cylindrical state or in an un-rolled planer state. While in the stable rolled cylindrical state, the map or plan can be effectively transported or stored. While in the stable un-rolled planer state the map or plan can be displayed without the need for a supporting surface such as a table or other flat surface. A particular need exists for a simple display device that resists the natural curling of the plan or map which results from being stowed in the rolled state.
Similarly, there is a need for a simple bi-stable hinging mechanism that could be used in various conditions and for various purposes. Such hinges would have a “self locking” feature and two stable positions without the need for additional mechanisms. Such a hinge applied to a simple container would insure full closure of the container. The container would also have a captured lid that cannot be misplaced.
In addition there is a need for a simple can or drum feeding mechanism that would allow effective storage and presentation of cans in confined spaces such as refrigerators, packaging containers, coolers or storage shelves.